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R/V Marcus G. Langseth: An Explanation of How Stuff Works

Author:
Tyler Poppenwimer

R/V Marcus G. Langseth,

31-May-13, Vigo, Spain

R/V Marcus G. Langseth: An Explanation of How Stuff Works

Hello again everyone. So, I was originally planning on talking about what life is like on the boat since we are docked here in Vigo, Spain and not much is going on. However, since life on the boat is about to change due to the actual research cruise starting and shifts beginning, I will hold off on that for a few more posts. Instead, this post, will better explain the streamers, modules, sections, birds, acoustic devices, and all of the other stuff that is used on the boat to conduct research. I will try to explain what all of these things do and how they work to map the bottom of the ocean floor. Also, I will be trying to upload pictures about some of the devices and equipment so that you can see what it is I am talking about.

The two main components that are used to map the bottom of the ocean floor are the guns, and the streamers (streamers have a diameter of approximately 4-5 inches). This boat has 4 sets of streamers and 4 sets of guns. The guns are basically air guns that when fired shoot a wave of sound towards the bottom of the ocean. This sound reaches the bottom and bounces back. Depending on the medium, the amount of sound energy that bounces back will change. The streamers have sensors that then detect the sound energy and pipes this information back to the main lab on the boat. This information is then used to figure out the depth and the material on the ocean floor.

In order to maximize the accuracy and amount of data the streamers collect, there are a number of different elements that are used in conjunction with the streamer. First is the tail buoy. The tail buoy is connected at the very end of the streamer and lies about 150-300 meters from the end of the streamer. Its job is to relay GPS information back from the end of the streamer to the boat so that the main lab can identify where the end of the streamer lies in relation to the boat. Next, on the streamers themselves, are the birds. The birds have three major functions; 1) they give a compass reading to the main lab, 2) they give a depth reading to the main lab 3) they control the depth of the streamer using rotating wings (here is where the name bird comes from). A bird is attached about every 300 meters and there are a total of 22 birds per streamer. Finally, comes the acoustic devices. There are five acoustic devices per streamer, two are near the tail-end, one is in the middle, and two are near the boat-end. The acoustic devices talk to each other between all the streamers so that the main lab can tell where the streamers are in relation to each other.

As the streamers are 6km long, they are built in sections. Each section is about 150 meters in length, and contains numerous sensors as well as two coils. The coils are used to attach birds and acoustic devices to the streamers. Each coil is not used and so there are extras in case a coil fails (coils cannot be replaced, only whole sections can). At the end of the sections are connectors. These connectors can connect from streamer to streamer, but it is necessary for power and for data transfer that a module is placed in between the connectors on the ends of sections. A module pretty much just connects the section, but I have no idea what is inside them. At the boat-end of the streamer comes the lead end. The lead end is basically a long cable that gives extra length to the streamer so that the streamer can be attached to the wings of the boat. The lead end also connects directly to the boat to relay power and information.

That is pretty much how the data collection is performed. After that, numerous computer programs as well as the researchers sift through the data and decipher its meaning. After all of this work, the output is a beautiful 3D map of the ocean floor in that region.

Well, I hope this helps explain everything a bit better. I know that what I have been saying gets quite technical. I hope you are all doing well and I will post again soon. Take care everyone.

- This is Tyler Poppenwimer, singing off –

P.S. If you want to track the Marcus G. Langseth, you can use one of these websites:

This material is based upon work supported by the National Science Foundation under Grant Numbers DRL/ITEST 1312333 and DUE/ATE 1104310. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.